Can i take drugs at work?

Many pain killers are also mind altering drugs, and if it creates a safety hazard, they can remove from the job until you are off the meds. They can't force you not to take them, though.

And as far as the military goes, if you are on pain killers, they probably will also put you light duty. And if not for the meds, the broken bone will definitely get you light duty.

A company can't legally stop you from taking medication. However, a company does not legally have to allow you to come to work if you are under the influence of medication that would affect your ability to work. See how that works?

They can't stop you, but if it in any way affects your performance, they can send you home until you no longer need them.

You may also fail any mandatory drug tests and they can fire you, even if you do have a medical excuse. They are not legally required to accept a doctor's note or any other excuse for taking drugs.

I know on jobs I have worked people taking Vicodin (with a prescription) were allowed to take it but could not drive company cars or operate machinery. but I have never heard of them not letting somebody work.

Either they accept that you have to take these medicines and let you work eespite this, or they have to give you extra time (sick-leave) off, but this also depends on the company you work for. Private companies are not always easy on this, while government agencies tend to accept this more easily. I am writing from the UK and things may be different in the US.

If you're working with heavy machinery, probably. Otherwise, I don't think so, unless you have another kind of job where you shouldn't be under the influence of painkillers.

Not if your employer has a policy against taking those drugs.